A 900-pound mountain of muscle, fur, and fury, the grizzly bear can sprint at 35 mph and decapitate a moose with a single swipe. Its claws measure four inches long and its bite can crush a bowling ball. Equally comfortable fishing for salmon or mauling anything foolish enough to wander near its cubs.

Unchanged for 200 million years because evolution couldn't improve the design, the saltwater crocodile is a 2,200-pound ambush predator with the strongest bite ever measured in the animal kingdom. Its death roll can dismember prey in seconds, and it can lurk motionless for hours before exploding from the water at terrifying speed. Dinosaurs went extinct; this thing didn't.